Telephone-exchange system



A. E. LUNDELL.

v TELEPHONE EXCHANGE SYSTEM. I APPLICATION FILED DEC. 27, 1916. 1,334,766. Patented 11:11:23, 1920.

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TELEPHONE EXCHANGE SYSTEM.

APPLICATION FILED DEC. 21. 1916.

1,334,766. Patented Mar. 23, 1920.

5 SHEETS-SHEET 5 Alba/4 Lynda/L UNITED STATES PATENT OFFICE.

ALBEN E. LUNDELL, OF NEW YORK, N. Y., ASSIG-NOR TO WESTERN ELECTRIC COMPANY, INCORPORATED, OF NEW YORK, N. Y., A CORPORATION OF NEW YORK.

TELEPHONE-EXCHANGE SYSTEM.

Specification of Letters Patent.

Patented Mar. 23, 1920.

Application filed December 27, 1916. Serial No. 139,093.

To all whom it may concern:

Be it known that I, ALBEN E. LUNDELL, a citizen of the United States, residing at New York, in the county of Bronx and State of New York, have invented certain new and 'useful Improvements in 'lelephone-EX- change Systems, of which the following is a full, clear, concise, and exact description.

This invention relates to telephone exchange systems in which automatic switches are used to establish connection, either wholly or in part, and is more particularly related to systems in which such switches are controlled by means of a sender located at a central oflicel The object of this invention is to provide an improved arrangement for testing such senders. In senders of the reverse impulse type, that is, senders which are operated in response to the movements of a switch or switches controlled by them, the arrangement has been such that after a switch has been positioned in accordance with a setting of the sender, circuit changes will take place 'both at the switch and at the sender whereby the switch may be controlled in another of its movements. Similarly, a succeeding switch or switches may be brought under the control of the sender, whose associated controlling device moves from position to position, upon the termination of the sending of each set of impulses.

In the present arrangement, it has been proposed to provide a testing circuit ar rangenient which will operate a sender in a manner similar to that in which it would be actuated in response to the movements of the switches normally controlled by it. i

The sender testing device, as disclosed in the present description, is designed to operate in connection with senders of the type used in power-driven systems of the semiautomatic type such as disclosed in Patent No. 1,168,319. The invention is not, however, to be restricted to use with any particular system, since it may be broadly applied to a large variety of systems.

The testing device includes a key set, a series of matching lamps, a series of progress lamps. a progress-controlling sequence switch and an impulse sending sequence switch. Although these devices are mounted in a suitable carriage of any convenient form, the present invention is concerned only with the circuit arrangement of the testing device.

The general operation of the arrangement is as follows: The jacks associated with the test box and indicated at 50 and 51 of Fig. 2 of the drawings, are arranged to be connected by double plug-ended links 52 and 53 to jacks 5a and 55 in Which-terminate lines rulming from the contact set of a cord finder. The cord finder will automatically hunt for calling terminals in a manner similar to that in which it seeks out a cord circuit in the regular operation of a semi-automatic system. The sender keys will be depressed in accordance with any desired number, and the person making the test will depress keys in the testing .device key set corresponding to the number of impulses to be sent.

The matching lamps consist of two rows of lamps, the lamps in one row being lighted during the sending of each series of impulses in accordance with the number set up by the testing operator. The lamps in the second series are lighted at proper times to indicate the number of impulses actually sent in response to the setting of the regular opcr ators key set. Thus, if a selection is properly made, this fact will be indicated by the lighting of adjacent lamps at the close of the sending of each set of impulses.

The progress sequence switch controls at its contacts, circuits to cause the lighting of matching lamps associated with the various keys in a definite order, and controls also a series of progress lamps which indicate the stage of operation and inform the operator which series of impulses is being sent at any time.

A feature of the present invention is the provision of a pair of relays to control the advance of the progress-controlling switch.

An added feature is the provision of lamp signals to check the operation of the apparatus.

A further feature is the provision of a key which, when depressed, serves to immediately stop the operation of the test and enables the person making the test to readily locate and remedy difficulties if trouble occurs during a certain portion of the operation.

It is thought that the invention will be testing arrangement embodying the present invention.

The operators key set, as shown in Fig. 3, is not 0 the ty commonly used, since in.

operation as or inarily practised, the number of impulses to be sent durin the first two selections are determined by t e depression of a. single key, and the number of impulses sent during the remaining five selections are determined by the depression of four keys in accordance with the numerical designation of the wanted line. Since, however, the keys associated with the testing arrangement are arranged tobe depressed in accordance with the number of impulses actually sent, it has been assumed that, in this case, the operator will also de ress keys in accordance with the number 0 impulses actually to be sent.

The regular operation of the sender to be tested, as used in setting up a connection between two subscribers, will first be described, after which its operation in connection with the testing device will be described.

If we assume that the number of the wanted subscriber is 3416, and that his substation is served through an ofiice whose trunks terminate in the .third sub-group of the fifth main group of terminals served by the switch shown in Fig. 1, the operation will be as follows:

The operator will depress district brush key 4 and district group, key 2. Since the number of the wanted line is 3416, a final switch must be seized which terminates in the second main roup and third sub-group of the contacts 0 an incoming switch at the office selected, and therefore incoming brush key 1 and incomin group key 2 will have to be depressed. t the final switch, the terminals of the wanted line will be found in a grou served by the fifth brush, and therefore nal brush key 4 will have to be depressed. Since the desired hundreds group has now been located, the depression of the No. 1 key in the tens column and the No. 6 ke in the units column will serve to control t e last two selections in obtaining the desired line.

The subscriber at substation 1, when desiring a connection, removes his receiver from the hook, whereupon line relay 2 is energized to cause the display of a line signal 3 in the well-known manner. An operator, one of whose cords is indicated at 0, upon observing the li hting of signal 3, inserts a plug 4 into a ack 5 associated with signal 3. A circuit is then completed from grounded battery, cut-off relay 6, sleeve contacts of jack 5 and plug 4, cord relay 7, to ground.

Relays 6 and 7 are energized in this circuit, eut-ofi' relay 6 operating to remove the control of line relay 2 from the calling subscriber, and relay 7 completing a circuit from grounded battery, power magnet of sequence switch 100, contact 102, front contact and armature of relay 7, to ground, for moving sequence switch 100 out of position 1 and into position 2, under the control of its normal spring 101. By depressing a listening key 8, the operator completes a talklIl circuit to the calling subscriber and may as the number of the wanted line. Upon learning that the desired subscribers number is 3416 in an ofiice, the trunks to which terminate in the third sub-group of the fifth main group of trunks of the district selector, she will depress keys in the ke set shown in .Fig. 3, as previously describe When the sequence switch 100 arrives in position 2, a circuit is completed from ground, contact 103, contacts 202, 203, winding of relay 9, to grounded battery.

Relay 9 is energized and at its right-hand armature and front contact completes a circuitfrom grounded battery, power magnet of sequence switch 200, contact 204, armature and front contact of relay 9, to ground, which moves sequence switch 200 from position 1 to position 2 under the control of its normal spring 201. In position 2 of sequence switch 200, a circuit is completed from grounded battery, up-drive magnet 10, contact 205, armature and front contact of relay 9, to ground, which causes the cord finder brush shaft 11 to be moved upwardly,

advancing brushes 12, 13, 14, 15 and 16 over terminals 17, 18, 19, 20 and 21 associated with the various cord circuits.

Relay 9, upon energization, locks itself over a path from-grounded battery, winding of relay 9, its left-hand armature and front contact, commutator 23 and brush 24, to ground, and this locking circuit is maintained in position 2 of sequence switch 200 through contacts 206, 215 and the left-hand armature and back contact of relay 22, to ground. When the cord finder brushes engage the terminals of the pro r cord, relay 22 is energized over a circuit rom grounded .battery, winding of relay 22, contact 207,

brush 12, terminal 17, contact 104, to ground, and immediately locks up,over a ath from grounded battery, winding of reay 22, contact 208, right-hand armature and front contact of relay 22, brush 13, terminal 18. contact 105, to ground. The-energization of relay 22 opens one branch of the locking circuit of relay 9, but this relay is maintained energized over a branch path from grounded battery, winding of relay 9, left-hand armature and front contact of relay 9, a conducting segment of commutator 23, brush 24, to ground, until brush 24 engages an insulating segment of commutator 23, at which time the brush will be accurately centered on the termmals of the desired cord. Relay 9 then deenerglzes, opening at its right-hand armature and front contact the circuit of up-drive magnet 10 and completing at its right-hand armature and back contact a circuit from grounded battery, power magnet of sequence switch 200, contact 209, right armature and back contact of relay 9, to ground, which moves this sequence switch from position 2 to position 3.

In position 3 of sequence switch 200, a circuit is completed from grounded battery, power magnet of sequence switch 300, contact 302, contact 210, to ground, for moving sequence switch 300 out of position 1 and into position 3, under the control of its normal spring 301.

The operator having learned the number of the wanted line and having depressed the proper keys. now depresses a start key 25, which completes a circuit from grounded batter', power magnet of sequence swltch 300, contact 303, contacts of key 25, to ground, which moves this sequence switch out of position 3 to position 4. Start key 25 also completes a circuit from grounded battery, power magnet of sequence switch 200, contact 214, contacts of key 25, to ground, which moves sequence switch 200 into position 4.

A circuit is now completed for the district line relay 26 over the fundamental circuit, from grounded battery, winding or relay 26. contact 106, conductor 27, terminal 20, finder brush 15, outer armature and back contact of the upper O counting relay, windings of stepping relay 28, contact 304, finder brush 14, terminal 19, conductor 29, contact 107, to ground. Relay 26 locks itself to conductor 27 through its left-hand armature and front contact and contact 108, and also completes a circuit from grounded battery, power magnet of sequence switch 100, conductor 30, contact 109, right-hand armature and front contact of relay 26, to ground, for moving sequence switch 100 out of position 2 and into position 3.

In position 3 of sequence switch 100, a circuit is completed from grounded battery, power magnet 31, contact 110, right-hand armature and front contact of relay 26, to ground. Brush rod 32 is moved upward under'the control of power magnet 31 and district brush col'umn, contact 305, arma ture and front contact of steppin relay 28, to ground. Relay 4 is energize and prepares a path for the No. 4 counting relay in the well-known manner.

As the brush rod 32 moved upwardly, the circuit of step ing relay 28 is intermittently shunted by a ranch of the locking circuit of relay 26, which extends through contacts 108 and 111, conductor 33, accurate centering segment 34, brush 35, to ground. The action of relay 28 results in the successive actuation of the counting relays in the well-known manner. When the upper O counting relay is energized, the branch of the fundamental circuit through stepping relay 28 is permanently broken, and when, a moment later, centering brush 35 engages an insulating segment of commutator 34, relay 26 is de'nergized, opening at its righthand armature the circuit of up-drive magnet 31 and maintaining brush'rod 32 in a position wherein the fifth set of brushes may be tripped. A circuit is also completed from grounded battery, power magnet of sequenc switch 100, conductor 30, contact 112, armature and back contact of relay 26, to ground, for moving this sequence switch from position 3 to position 4. A circuit is now completed from grounded battery, winding of trip magnet 49, contact 118, to ground, to operate the trip rod to release the positioned set of brushes.

The energization of the upper 0 counting relay completes a circuit from grounded battery, power magnet of sequence switch 300, inner armature and front contact of the upper O counting relay, contact 306, to ground, which moves this sequence switch from position 4 to position 6.

\Vhen sequence switch 300 leaves position 4, the locking circuit of the counting relays is broken at contact 307 and they are de'e'nergized.

In position 4 of sequence switch 100, and in position 6 of sequence switch 300, relay 26 is again energized over the fundamental circuit previously described, and again locks itself to conductor 27. pleted from grounded battery, power magnet of sequence switch 100, conductor 30. contact 109, armature and front contact of relay 26 to ground, for moving this sequence switch out of position 4 and into position 5. v In position 5 of sequence switch 100, the

A circuit is also comcircuit of up-drive magnet 31 is again closed from grounded battery, winding of magnet 31, contact 110, armature and front contact of relay 26, to ground, again causing upward motion of the brush rod 32.

The closure of the fundamental circuit again causes the energization of step ing relay 28.. A circuit is then completed from grounded battery, winding of the No. 2 counting relay, contacts'of key No. 2 1n the district group column, contact 308, armature and front contact of steppin relay 28, to ground. Counting relay No. 2 is energized and prepares a circuit for the No. 2' counting relay in the well-known manner. During the upward motion of the brush rod, stepping relay 28 is again intermittently shunted by a branch of the lockingcircult of relay 26, through contacts 108, 113, conductor 36, segment 37, brush 38, to ground The action of stepping relay 28 results in the successive energization of the counting relays, and when the O counting relay is energized, it opens at its outer armature the lower branch of the locking circuit of relay 2-6. When brush 38 engages an insulat-.

ing portion of commutator 37, relay 26 is deenergized, opening at its ri ht-hand armature the circuit of the uprive magnet 31, and stopping the brush shaft with the fifth set of brushes at the bottom of the third sub-group of trunks, the trunks therein leading to the desired office. The O counting relay at its inner armature and front contact completes a. circuit for movlng sequence switch 300 from position 4 to po-v sition 6. Relay 26, upon deenergization, also completes a circuit from grounded battery, power magnet of sequence switch 100, conductor 30, contact 112, right-hand armature and back contact of relay 26, to ground, formoving this sequence switch out of position 5 and into position 11.

It is to be understood that the brush rod 32 is again advanced to hunt for an ldle trunk in the selected group, in some sequence switch position between 5 and 11, and upon the seizure of such trunk is advanced to position- 11, but it has not been considered necessary to disclose this well-known operation.

The incoming switch indicated by brushes and terminals at 39, is operated in accordanoe with the setting of the keys in the incoming brush and incoming group columns in positions ,8 and 10 of the sending sequence switch 300. Hunting then takes place at the incoming switch, and when an idle final switch has been seized, it is set in accordance with the designation of the final brush, tens and units keys, in positions 12, 14 and 16. of the sender sequence switch. The final switch is indicated by brushes and terminals at 40 in Fig. 1.

weaves When the sender sequ ence switch is moved out of position 16 upon the final energization of the O counting relay, the sender sequence switch moves from position 16 to position 1. In-passing through positions 17 and 18, a circuit is completed from grounded battery, power magnet of sequence switch 200, contact 309, to ground, which moves sequence switch 200 from position 4 to position 8.

In position. 8 of sequence switch 200, a circuit is completed from ground, contact 211, brush 16, terminal 21, conductor 41, contact 114, power magnet of sequence switch 100, to grounded battery, which moves sequence switch 100 from position 11 to position 16.

After the sender sequence switch 300 has returned to normal osition, a circuit is completed from groun ed battery, down-drive magnet 42, contact 310, contact 212, to ground. Brush rod 11 is returned to normal position under the control of magnet 42, and when it reaches normal position, a cir-. cuit is completed from grounded battery, power magnet of sequence switch 200, contact 213, commutator segment 43, brush 44, to ground, which moves sequence switch 200 from position 8 to position 1, and breaks the circuit of down-drive magnet 42.

Se uence switch 100 is now in position 16, w iich is the talking position, and it hasbeen assumed that the switches 39 and 40 have moved into their talking positions after the called subscriber has been successfully signaled. The connection is now complete and the parties may converse.

At the conclusion of conversation, both parties replace their receivers and the operator at O is informed by the li hting of supervisory signals (not shown controlled by supervisory relays 45 and 46, that connection 1s not longer desired. She thereupon removes plug 4 from jack 5, causing the deenergization of relay 7, which completes a circuit from grounded battery, power magnet of sequence switch 100, contact 115, armature and back contact of relay 7, to ground, for moving this sequence switch from position 16 to position 18. A circuit is now completed from grounded battery, down-drive magnet 47, contact 116, to ground.

The brush rod 32 is restored to its normal position, and on reaching normal osition a circuit is closed from grounde battery, power magnet of sequence switch 100, conductor 30, contact 117, commutator segment 48, brush 38, to ground, which moves this sequence switch from position 18 into position 1, thereby opening the circuit of m net 47. The restoration of a district swiz i causes the restoration of switches 39 and 40 in the well-known manner. All parts of the apparatus have now been restored to their normal positions and are ready for re-use.

It now, it is desired to test the accuracy of operation of the sender, this may be done by connecting jacks 54 and 55 With jacks 50 and 51 by means of link connectors 52 and 53.

Assuming that the same number of impulses are to be sent as in the previous setting of the connecting switches, the same keys will be set in the operators key set, shown in Fig. 3, that is, key No. 4 in the district brush column, key No. 2 in the district group column, key No. 1 in the incoming brush column, key No. 2 in the incoming group column, key No. 4 in the final brush column, key No. 1 in the tens column and key No. 6 in the units column. Corresponding keys will be depressed on the test box key set shown in Fig. 5.

The testing operator now depresses start key 56, whereupon a circuit is completed from grounded battery, power magnet of progress-controlling sequence switch 400, contact 402, contacts of start key 56, to

ground, which causes sequence switch 400 to w more out of position 1 and into position 2, under the control of its normal spring 401. it. circuit is now completed from grounded battery, winding of relay 9, contacts 203 202. sleeve contact of jack 55, sleeve conductor of link 53, sleeve contact of jack 51,

contact 403, to ground. Relay 9 is ener gized and completes a circuit from grounded battery, power magnet of sequence switch 200, contact 204, right armature and front contact of relay 9, to ground, which moves the sequence switch out of position 1 and into position 2. Relay 9 looks up over a circuit from grounded battery, winding ot relay 9, its loft-hand armature and front contact, commutator 23 and brush 24, to ground, and this locking circuit is maintained in position 2 of sequence switch 200 through contacts 206 and 215, and the left-hand armature and back contact of relay 22, to ground.

In position 2 of sequence switch 200, a circuit is completed from grounded battery, up-drive magnet '10, contact 205, armature and front contact of relay 9, to ground, which causes the cord finder brush shaft 11 to be moved upwardly, advancing the brushes 12, 13, 14, 15 and 16 over terminals 17, 18, 19, 20 and 21 respectively. When the cord finder brushes engage the terminals to which the test jacks 54 and 55 are connected, relay 22 is energized over a circuit from grounded battery, winding of relay 22, contact 207, brush 12, terminal 17, ring 'contact of jack 55, ring conductor of link minal 18, tip cbntact of jack 55, tip conductor of link 53, tip contact of jack 51, contact 405, to ground. The energization of relay 22 opens one branch of the locking circuit of relay 9, but this relay is main.. tained energized over a branch path, as previously described, until the brush set is accurately centered on the desired terminal set. Relay 9 then denergizes, opening at its right-hand armature and front contact the circuit of up-drive magnet 10, and completing at its ri ht-hand armature and back contact a circuit to move sequence switch 200 from position 2 to position 3, as previously described.

From this oint the operation is the same as previous y described until sequence switch 300 arrives in position 4 at which time sequence switch 200 is also in position 4. At this time relay 57 is energized over the fundamental circuit, this circuit extendmg from grounded battery, winding of relay 57, contact 502 conductor 60, contact 406, tip contact of jack 50, tip conductor of link 52, tip contact of jack 54, terminal 20,

brush 15, conductor 58, outer armature and back contact of the O counting relay, winding of stepping relay 28, contact 304, brush 14, terminal 19, ring contact of jack 54, ring conductor of link 52, ring contact of jack circuit, relay 57 looking itself to conductor 60 through its left-hand armature and front contact, while stepping relay 28 completes a circuit for the No. 4 counting relay through the closed contacts of the N0. 4 key in the district brush column, as previously described.

Relay 57 also completes a circuit from grounded battery, power magnet of impulse sequence switch 500, left-hand armature and back contact of relay 59, contact 503, right-hand armature and front contact of relay 57, to ground. for moving sequence switch 500 out of its normal posi tion and into a position determined by the operation of the sender shown in Fig. 3.

Impulse sequence switch 500 may be a sequence switch of the usual type of construction, and is arranged to continue rotation, after being started, as long as relay 57 is energized, and operates to shunt out the stepping relay by the intermittent closure of its contact 504 as will now be described.

It should be noted, however, that relay 57 will in no case remain energized after the twelfth position is passed, since the function of relay 57 is to stop sequence switch 500 in a position to correspond with the number of impulses counted off by the counting relays in Fig. 3.

When sequence switch 500 reaches position N1, stepping relay 28 is deenergized to permit the energization of the No. 4 counthand armature and front contact of relay and in turn energizes the ing relay, sinceitis shunted by a path from grounded battery, winding of relay 57,1eftrelay. In position 01} of the sequence switch 01}, the

500, steppm relay 28- is again shunted and allows the 14%). 3 counting relay to energize. When se uence'switch 500 leaves posltion o. 2 counting relay is energized,

ductor 71, contact 508, to ground. Bela 69 is energized and locks itself to groun at its lower armature and front contact, and at its upper armature and front contact th1s process continuing until the O counting completes a circuit from grounded battery,

relay isen'ergized, which will take place when sequence switch 500 arrives in position 3%. .The energization of the .0 counting relay results inv the ermanent o ening of relay'5 and, 500 leaves position 31}, the upper branch path of relay 57 is broken, whereupon it deenergizes and sequence switch 500 will move into position 4 under the control of its-normal spring 501 I and stop in this position. a

With sequence switch 400 in position 2, lamp 61 is lighted over a circuit from grounded battery, lamp 61, contact 408,-to ground, indicating to the testing operator that the progress-controlling sequence switch 400 is in position 2, in which position the district brush-selecting impulses are to be sent.' At the same time a circuit exists for matching lamp 62 from grounded battery, lamp 62, closed contacts of .district'brush ,key No. 4, conductor 63, contact 408, to ground. The lighting of these two lamps informs the testing operator that the district brush-selecting impulses are being sent at this stage of operation, and that the No. 4 key has been de ressed.

With sequence switc 500 in position 4, a

circuit will be completed for matching lamp 63, adjacent to lamp 62, from grounded batter lamp 63, contact 505, conductor 65, rig it-hand armature and back contact of relay 57, to ground. The lighting of lamp 63 informs the testing operator that the desired number of impulses have been correctly sent. v

A circuit is also completed at this. time for relay 59 from grounded battery, winding of relay 59, conductor 66, closed con tacts of key 87, contact 409, conductor 67, closed contacts of key No. 4 in the district brush column, conductor 68, contact 505, conductor 65, right-hand armature and back contact of relay 57, to ground. Relay 59 completes an alternate energizing circuit for itself from grounded battery, winding of relay 59, contacts 506 and 410, right-hand armature and front contact of relay 59, to

round. Relay 59 also completes a circuit rom grounded battery, power magnet of sequence switch 500, le t-hand armature and front contact of relay 59, contact 507, confront contact of relay 69, contact 412, to

ground, for moving sequence switch 400 rom position 2 to position 3.

In position 3 of sequence switch 400, the locking circuit of relay 69 is broken at contact 411, and a circuit is established from grounded battery, power magnet of sequence switch 500, left-hand armature and back contact of relay 59, contact 511, lower armature and back contact of relay 70, contact 413, to ground, which moves sequence switch 500 out of position 16 into its normal position.

The energizationof the O counting relay completed a circuit from grounded battery, power magnet of sequence switch 300, inner armature and front contact of O counting relay, contact 306, to ground, which moves sequence switch 300 from position 4 to position 6.

With sequence switch 400 in position 3, a circuit is completed for progress lamp 73 from grounded battery, lamp 73, contact 414, to ground, and a circuit is com leted for matchin lamp 74 from grounde battery, lamp 4, closed contacts of district .brush key No. 2, conductor 75, contact 414, to ground. The lighting of progress lamp 74 informs the testing operator that the district group impulses are to be sent next, and the lighting of lamp 74 shows which lamp in the second series of matching lamps should next be lighted.

When sequence switch 500 arrives in its normal position and the sender sequence cuit, as previously described. As before, the I circuit of stepping relay 28 is intermittently shunted by the action of contact 504, and when the O counting relay is energized, whlch occurs when sequence switch 500 leaves position 1g, relay 57 is deenergized and sequence switch 500 will come to rest in position 2. At this time a circuit will be completed from rounded battery, lamp 76, contact 512, conductor 65 and armature and back contact of relay 57, to ground, the lighting of lamps 74 and 76 again ind1- eating to the testing operator that the correct number of impulses have been sent, lRelay 59 is energized and locks up, as before. When sequence switch 500 reaches position 15, relay will be energized over a circuit from grounded battery, contact 415, winding of relay 70, lower armature and back contact of relay 69, conductor 71, contact 508, to ground. It willbe seen that if relay 69 failed to deenergize, this energizing circuit for relay 70 cannot be completed, and thus relays 69 and 70 interact to insure positive control of progress-com trolling sequence switch 400. Belay 7O locks itself to ground at its upper armature and trout contact until sequence switch 400 reaches position 8, irrespective of the position of sequence switch 500. A circuit is now completed from grounded battery, winding of the power magnet of sequence switch 500, contact 509, lower armature and front contact of relay 70, contact 413, to ground, for moving sequence switch 500 out of position 15 and into position 16.

In position 16 of sequence switch 500, a circuit is completed from grounded battery, power magnet of sequence switch 400, conductor 72, contact 510, lower armature and front contact of relay 70, contact 413, to ground, for moving sequence switch 400 out of position 3 and into position 11.

On leaving position 3, relay 70 is deenergized and a circuit is completed from grounded battery, power magnet of sequence switch 500, left-hand armature and back contact of relay 59, contact 511, upper armature and back contact of relay 69, contact 412, to ground, for moving sequence switch 500 out of position 16 and back to its normal position.

The testing operation continues in this manner until all the sets of impulses have been sent, the circuits operating in a manner similar to that described until the last tesbt is made in position 15 of sequence switch 40 out of position 15, it returns to its first or normal position and the testing apparatus is in a condition for re-use. a

If for any reason, the testing operator desires to stop the progress of a test while the impulse sequence switch is operating, he

may do so by depressing key 97. Relay 59 will then be energized over a circuit from grounded battery, winding of relay 59, conductor 66, closed contacts of key 97, to ground. Relay 59 at its left-hand armature, opens the circuit of the power magnet When sequence switch 400 is moved to the occurrence of such-trouble, he may readily determine what the nature of the trouble is, since all parts of the apparatus will be held in the position in. which they were when the trouble was noted.

: If, for any reason, the testing operator desires to prevent the automatic progress of the test, he may do so by depressing key 87, which, in opening its contacts, prevents the closure of the circuit of'relay 59, and will, therefore, hold sequence switch 500 in whichever position it came to rest until such time as the operator wishes to allow the test to continue.

What is claimed is:

1. In a testing system, means for sending impulses, a sending device arranged to C011 trol said means to send a plurality of sets of impulses, a testing device, means to operate said testing device to test the correctness of the first set of impulses sent, means to ad Vance the operation of said testing device to a stage wherein the correctness of the next set of impulses may be tested, and means to repeat the advancing operation of said testing device upon the completion of thesending of each set of impulses until all the sets of impulses have been sent.

2. In a testing system, means for sending impulses, a sending device arranged to control said means to send a plurality of sets of impulses, a register, a control switch therefor, means to position said register in response to a set of impulses, means oper ated in accordance with the settings of said register to indicate whether or not the successive sets of impulses have been correctly sent, and means to advance said control switch to a position wherein said register may receive the next set of impulses.

3. In a testing system, a sending device, a control switch therefor, means to operate said sender in certain positions of said control switch, a register, a controlling switch therefor, means to position said register in accordance with the operation of said sender, means operable upon the termination of the sending of a set of impulses to move said sending control-switch to a position wherein a second set of impulses may be sent, means operated in accordance with the setting of said register to indicate whether or not the set of impulses have been correctly sent, means to restore said register to its nor- 7 mal position, and means operable during the return of said register to advance said register controlling switch to a position where in reoperation of said reglster may take place.

4. In a testing device, two series of lamps, means to light a desired lamp in one of said.

series to indicate a desired operation of the device being tested, and means to light a lamp in the other of said series'in accordance with the operation which occurs, the series of lamps being so arranged that when the desired operation takes place adjacent lamps will be lighted.

5. In .a testing system, a sending device, a control switch therefor, means to successively operate-said sending device, a testing operators key set, a testin device including a register and a controlling switch therefor, a series of lamps, means to light a desired one of said lamps in accordance with the setting of said -key set, a second series of lamps, means to position said register in accordance with the operation of said sender, means to light one of said second series of lamps in accordance with the setting of said register, said two series ,of lamps being placed in such relation.that adjacent lamps will be lighted when a set of impulses is correctly sent.

6. In an automatic telephone exchange system, a sending device, a controlling switch therefor, an operators key set, means to successively operate said sending device in accordance with the setting of said-key set, a testing operators key set, a testing device, includm a register and a controlling switch there or, a series of lamps, there being one for each digit of the testing operators key set, means to light a desired lamp in each position of said register controlling switch, a second series of lamps, means to position said register in accordance with the operation of said sender, means to light one of said lamps in accordance with the setting of said register to indicate whether or not a set of impulses has been correctly sent,

trolling switch therefor, means to o eratesaid register in certain positions of sai controlling switch, means to advance said controlling switch, a pair of relays to control the advance of said controlling switch, and an interconnection of said rela s such that said controlling switch cannot e advanced if said relays have not operated correctly.

8. In a switch controlling system, a switch, means to'advance said switch, a pair of relays to control the advance of said switch, said relays being alternately energized to control alternate steps of said switch, and an interconnection between said relays such that one of said relays cannot be energized until the release of said other relay.

9. In a testing system, a revertive impulse controlling device, an impulse sending means, means to operate said controllin device to control the impulses sent by sai sending means in successive sets of impulses, a testing device, and means to operate said testing device to test the accurac of the successive operations of said contro ling device.

10. In a testing system, a revertive impulse controlling device, an i ulse sending means, means to operate said evice to control the impulses sent by said sending means in successive sets of impulses, a testin device, means to operate said testing device to test the accuracy of the successive operations of said controlling device, and manu ally controlled means to stop the operation of said devices during the sending of a set of impulses.

In witness whereof, I hereunto subscribe my name this 26th day of December A. D.,

ALBEN E. LUNDELL. 

